Weld Test Samples

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I plan to build a roll cage for a track car.My welds (MIG) do not have to be certified but I would like some assurance that my welds are up to the task.I would like to make test samples and destructively test them.Does anyone have a design of test sample and testing methodology that can be completed in the shop without requiring any specialized equipment.1.5" .095 mild steel tubeThanks
Reply:Originally Posted by astonI plan to build a roll cage for a track car.My welds (MIG) do not have to be certified but I would like some assurance that my welds are up to the task.I would like to make test samples and destructively test them.Does anyone have a design of test sample and testing methodology that can be completed in the shop without requiring any specialized equipment.1.5" .095 mild steel tubeThanks
Reply:Pretty much every NHRA approved cage I've ever seen was built out of 1 3/4 .120 wall DOM.--Wintermute"No man's knowledge here can go beyond his experience." - John Lockewww.improvised-engineering.comManufacturer Agnostic:Blood----------Sweat---------Tears----|------------------|----------------|----Lincoln Red, Miller Blue, Esab Yellow
Reply:I have built a lot of cages not for racing but for rock crawlers and would use nothing but .120 DOM or Chromoly at least 1 1/2 Period! Also its how you design the cage is everything, Triangulation is your friend.
Reply:The tubing must be seamless ERW or DOM.The car will not be used for racing and I am familiar with the requirements.Now back to those test samples.
Reply:http://www.customcages.co.uk/roll-cages/certificationhttp://students.sae.org/competitions...es/welding.pdfLooks to me like you would weld some samples of the joints you will be making in the cage, and then doing bend tests. It would be worth it to consult an engineer or a shop that designs and builds them once you come up with a final design and see if they spot any problems... lest you want a 1-1/2 tube going through your head when you roll... A roll cage is serious business. Unless you have worked at a design / fab shop for them for a number of years, and know exactly what goes into them, I think its a project better left to a shop. Im not trying to tell you what to do, cause i dont know you, and i dont know your skill level, but im just putting my $.02 out there.
Reply:The first part of any weld test would be a visual inspection. So what do your welds look like now? If you can't the visual no point in bend testing.
Reply:Originally Posted by slow6ihttp://www.customcages.co.uk/roll-cages/certificationhttp://students.sae.org/competitions...es/welding.pdfLooks to me like you would weld some samples of the joints you will be making in the cage, and then doing bend tests. It would be worth it to consult an engineer or a shop that designs and builds them once you come up with a final design and see if they spot any problems... lest you want a 1-1/2 tube going through your head when you roll... A roll cage is serious business. Unless you have worked at a design / fab shop for them for a number of years, and know exactly what goes into them, I think its a project better left to a shop. Im not trying to tell you what to do, cause i dont know you, and i dont know your skill level, but im just putting my $.02 out there.
Reply:Originally Posted by astonThe tubing must be seamless ERW or DOM.The car will not be used for racing and I am familiar with the requirements.Now back to those test samples.
Reply:What the hell is going on this week?  Is everyone deciding to put cages in their cars?Read this thread:http://weldingweb.com/vbb/showthread.php?t=68291 Originally Posted by SundownIIIDon't get me wrong.  They are just as ill informed about politics as they are about welding, they just post more on that subject.
Reply:Check with SCCA but if your under somewhere around 2400 pounds i BELIEVE that tubing size is ok. Like I said check with the SCCA rule book, cant just spout of numbers and say its to thin without even knowing the car.. ERW means electrical resistance welded. There is tube that is extruded from a solid round bar with no weld seam, and there is tube with.. well a weld seam. ERW and DOM are both that. Welded seam tubing. DOM starts out as erw tube but is generally of higher quality than your average erw tube once it is refined and cold finished.I dont care how well you can weld a tube joint on the bench, wait until you are upside down in the car trying to weld a joint.. Totally different.. I would recommend practicing a lot of joints before you think about building a cage. Design is also extremely important, I like to make every tube intersect pretty much ontop of each other.. I see people put them all next to each other and that is just a lot of shear load if it took a hit.As far as testing I have just made a joint like this -----------|----------- and put pressed on the center.. Becareful if you use anything in a press it can get dangerous very quick. I dont like that method anymore unless you find a control method incase things go flying, like a scatter shield...Or the old hammer method but in my opinion you should not be able to break a tube joint with a hammer... Unless its a huge sledge, my guess is it will mangle the hell out of the tube..If you build a cage correctly, you really can minimize joint stress and load on the welds.. I just googled this and found a nice picture, nice design, all impact zones are triangulated and not dead headed. Kind of weird on the harness bar but I suppose it works. Attached ImagesHTP Invertig 201Lincoln Idealarc SP250Miller 180 AC StickBy farmall:They should have held the seagull closer to the work, squeezing evenly for best deposition.
Reply:Looked at that cage design I posted a bit more, the harness bar should be from the main hoop bend to the center of the X, and from that point on the hoop is where you would drop your door bar to the lower corner of the a pillar.. Nothing to keep the cage from folding inward on a hard side hit... Here is another reason why building a cage is serious business. Looks like the car took a SERIOUS impact (obviously) and the roof had no support other than the a pillar.. Need what is called an "FIA bar, which goes from the a pillar bend to somewhere on the door bar, I ran mine on top of the "nascar" door bars, right on top of my tube junction, as well as many gussets in this regionIn this pic a bar running from the a pillar bend to the tube junction on the door bars on both sides would have done a lot to prevent this, would have needed a good overhead diagonal or an X as well Attached ImagesLast edited by fordman; 01-09-2012 at 06:17 AM.HTP Invertig 201Lincoln Idealarc SP250Miller 180 AC StickBy farmall:They should have held the seagull closer to the work, squeezing evenly for best deposition.
Reply:Originally Posted by wintermutePretty much every NHRA approved cage I've ever seen was built out of 1 3/4 .120 wall DOM.--Wintermute
Reply:Thanks for the replies.First, to address the main concerns:1) The tubing is specified by the regulations I am required to follow. Other regulations have other specifications but they do not apply.2) I am not designing the cage. I am purchasing the cage as a kit, for my exact application. I believe all the appropriate engineering has been applied to the design. I am confident in the supplier company, their position in the industry and the fact that dozens, maybe even hundreds of their cages have passed inspection. Other cage designs may follow different strategies but they do not apply.Which brings us to the installation. I think I have sufficient fabrication skills, but it's *my* head that's at stake here, so I want proof. Which brings us to test samples.Thanks for the excellent information on test samples posted so far. When my tests are complete, I have two sources that I will use to help evaluate the results.
Reply:Well, if you want to be absolutely sure of your welds, you could always take a sample down to the nearest radiography weld testing facility and have them do a test on it (either destructive or non-destructive).  There's PNL in Phoenix, I'm sure there are a few in Tucson as well.--Wintermute"No man's knowledge here can go beyond his experience." - John Lockewww.improvised-engineering.comManufacturer Agnostic:Blood----------Sweat---------Tears----|------------------|----------------|----Lincoln Red, Miller Blue, Esab Yellow
Reply:Originally Posted by wintermuteWell, if you want to be absolutely sure of your welds, you could always take a sample down to the nearest radiography weld testing facility and have them do a test on it (either destructive or non-destructive).  There's PNL in Phoenix, I'm sure there are a few in Tucson as well.--Wintermute
Reply:Post results!!   When you get them :]
Reply:Good to hear PNL will be taking care of you.  Please let us know the results of the test.  Get pictures of the part after the failure test as well, it'll be good to see.--Wintermute"No man's knowledge here can go beyond his experience." - John Lockewww.improvised-engineering.comManufacturer Agnostic:Blood----------Sweat---------Tears----|------------------|----------------|----Lincoln Red, Miller Blue, Esab Yellow
Reply:I stated the cost incorrectly. PNL charge $125/hr for tensile testing, min 1hr. They will test as many samples as I send.
Reply:My test samples are finally ready. I'll send them off to PNL tomorrow. Attached Images
Reply:Good luck with your tests, but I see a lot of areas that can use some more work in those picts. I see a lot of signs of inconsistency in the 1st 3 from the left. I circled the biggest issues I see. The right ones look a bit better, but still look like they need more work. The blue line point to an area that looks tall and cold to me, but it might be an illusion from the pict. Close ups of the pieces would help as well as views of both sides.With what I see in these I'll make a guess and general observation... I'm betting you did these sitting at a bench, probably in the flat position like most guys do when welding. Maybe you did them in position like 5G or 6G. When you go to do the real thing however, you will have no choice but to do the welds in position, probably while you lay on your back bent over, or crouched in an awkward position at best. All those inconsistencies I see in you test samples will suddenly magnify themselves. If you can't make nice consistent welds on a bench, you'll never do it contorted in a strange position.Personally I'd save the $125 test fee and run more practice pieces 1st. I just don't think you are quite there yet with most of these. If you are serious, do the test pieces exactly like you would do them in the real world. Tack them up under your table and then weld them up while trying to work around the table legs and laying on your back. Attached Images.No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:waiting for the results on those Miller Xmt 350Lincoln Ln-25Ahp 200xSmith Gas Mixer AR/HTig is my Kung FuThrowing down dimes and weaving aboutInstagram http://instagram.com/[email protected]
Reply:Originally Posted by astonThe tubing must be seamless ERW or DOM.The car will not be used for racing and I am familiar with the requirements.Now back to those test samples.
Reply:These were done in a 6G position mounted in a bench vice. I had to sit on the floor and work overhead. Prior samples were cut apart and checked for penetration, I have a box full. So I think I'm ready. Lets see what the weld efficiency is.
Reply:did you get the results back yet?Originally Posted by allred27did you get the results back yet?